One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10,15,18)(11,14,17,23)(12,13,16,22)(19,20,21,24)(25,26)(27,31)(28,36)(29,33)(30,35)(32,38)(34,39)(37,40)(1,2)(3,7)(4,8)(5,6)(9,11,15,17)(10,14,18,23)(12,19,16,21)(13,20,22,24)(25,27)(26,30)(28,34)(29,35)(31,33)(32,39)(36,40)(37,38)(11,17)(14,23)(19,21)(20,24)(25,27,29,35)(26,30,33,31)(28,34,38,37)(32,39,36,40)(1,3,5,4)(2,7,6,8)(9,12)(10,13)(11,19)(14,20)(15,16)(17,21)(18,22)(23,24)(25,27)(26,31)(28,37)(29,35)(30,33)(32,39)(34,38)(36,40)(1,3,5,4)(2,7,6,8)(9,13)(10,16)(11,20)(12,18)(14,21)(15,22)(17,24)(19,23)(25,28)(26,32)(27,34)(29,38)(30,39)(31,40)(33,36)(35,37)(1,4,5,3)(2,8,6,7)(9,14,15,23)(10,17,18,11)(12,20,16,24)(13,21,22,19)(25,26)(27,31)(28,32)(29,33)(30,35)(34,40)(36,38)(37,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.